parker



J. E. PARKER Aug. 7, 1934.

MULTIPLE WAVE DETECTION AND TRANSMISSION APPARATUS 2 Sheets-Sheet 1 Original Filed March 23, 1927 Fig.1

L 3 rm/mszs mo L ax/11916 ma ll'l lllllrnll L Y FiqZ James 5 Parker INVENTOR ATTORNEYS, i

J. E. PARKER Re. 19,266

MULTIPLE WAVE DETECTION AND TRANSMISSION APPARATUS Aug. 7, 1934.

Original Filed March 23, 1927 2 Sheets-Sheet 2 Fig. .3

James 5 Parker IN V EN TOR.

Maw

' ATTORNEYS.

Reissued Aug. 7, I934 MULTIPLE; WAVE DETECTION. AND

. TRANSMISSION James E. Parker", Washington; D. 0.

Original No. moasi'ijdatea February 19,1929, Serial No. 177,752, March'23, 1927.- Application for reissue February 18, 193l, Serial No. 516,776

11 Claims. (013250-91 My invention relates broadly to multiple wave transmitters and detectors and more particularly to the circuits used in each and in the apparatus constituting a combination of the two.

It is well known that the detection of radio signals transmitted by distant broadcasting stations is subject to interference caused by the response of the detecting circuits to disturbances arising from nearby or powerful transmitting stations, from static and strays'or from miscellaneous sources of energy radiation. i

The loop receptor, the unidirectional receiver, loose coupled circuits in cascade, acceptor and rejector circuits, wave-traps, shielding and other methods of filtering and obtaining directive and selective reception have been resorted to with results that have-not been satisfactory.

The object of my invention is the production of a circuit in which detection or transmission may be accomplished with the reduction of extraneous interferenceto a minimum heretofore unattained.

' Another object of my invention is a new and novel method and means for accomplishing selective detection'and amplification of signals consisting in part of utilizing separately or in' combination the'additive and the subtractive results and efiects of mutual inductance ina c'oil system.

- Further objects of my invention will appear more fully hereinafter as the description of the method and apparatus is developed.

My invention consists-substantially in the construction, combination and arrangement of parts associated therewith or as will be more fully hereinafter set forth as shown-by the accompanying drawings and finally pointed out in the appended claims. 1 1 ,1' j

Reference. is .to be had to the accompanying drawings forming a part of this speciflcationin which like reference characters indicate cor-re sponding parts throughout the several views and inwhich: Y i p Figure 1 is a circuit diagram of my invention-as applied to a simple receiver circuit r Figure 1a is a modificationth'ereof'; Figure 2 is a further modificationthereof Figure 3 is a combined transmitter andreceiver circuit embodying the principlesof my invention;

- Figure 4 is a modification thereof. M

It is known that two inductances, if brought into relationship with each other, ma'y have a total value of inductancesgreater than thefsuni of the two individual sections or that by reversing the position 'of'one' section, 'thetotalvalue of inductance may be-lessthan that of 'thei'algebraic sum of the values of the two sections. This effect is typical of the functioningof a variometer in which the reacting inductances are movable relativeto each other.

My invention covers the method and means for obtaining greater and lesser values of inductance without requiring a change in the position or relationship of the sections that comprise the coil system, and the utilization of. this method and meansforobtaining a signal free from undesir able interference, or the reduction to a minimum of the effect of such'interference, with the highest degree of efliciency' consistent with simplicity of construction and operation;

Referring particularly to Figure 1 in which is shown asimple solenoid type of inductance in combination with a capacity or capacities, L designates accil system in which the total inductance is less than that of the sum of the inductance of anytwo sections such as a -.-b plus be, or H plus c.'e,.each considered separately.

' In parallel with theycoil L are a plurality of condensers C and C connected in series. The electrical center of the condenser system is connected to the electrical center of the coil system by theconnection' c'c The grid 6 of the vacuum tube 1v is connectedto the point 0 of the coil system'or may be connected to the point e of the condenser system. The filament of the vacuum tube is connected-to the point e of the coil system. 85. The plateofthe vacuum tube is connected'through the-coil 1 L through a source of plate current supply .to the. filament of'the vacuumtube.

The circuit L (C plus C is responsive to the frequencies-to which it is tuned. This .resonant 9c efiectdepends upon the LC values involved, relative-to the-points upon the coil that are connected to the condensers. l 1 "When the circuit .is tuned to resonance for'a particular frequency points a and 6 will. be at a particular :instant, at equal and opposite potentials relative'to each other. -At the same given instant the potentials at points mandge are equal and opposite-with respect to a midway point e; points a and c are equal and opposite with'respect to a midway point 1;; points 0 and e are equal and opposite with respect to a midway'point d; and points'b and dare equal and opposite with respect to a midway point r a When" the inductance of-the section ac is equahtothat of c".e and the capacity of condenser C isequal to the capacity of condenser C the potentials atpoints c-a'n'd c are equal and of like polarity at any given instant. Points '0 and 0" may therefore be connected together without any flow of current between the two. A switch 3 may be included, as shown, to open or close this connection for securing certain functions described hereinafter.

In the following description, the frequency at which the points a and e are equal and opposite in potential and polarity will be referred toss the A frequency. The coil L is excited by a current of the A frequency through any well known means, such as by capacity or inductive coupling to a suitable circuit, by the functioning of the coils as loops, or by being self-excited and oscillating in conjunction with a vacuum tube circuit. 'Ihe coil L functions as a regenerative coupling to the coil L The coil L is capable ofrevolution through 180 degrees about its axis from a position parallel to coil L through a position at right angles thereto, and to a position parallel to the coil L but opposite to its original position.

The plate 8.-of vacuum tube 1 is connected to the filament '7 of thevacuum tube through the coil L3 and a source of plate current supply. The filament 7, in turn, is connected to the. point e on the coil L The grid may be connected to points a, b, c, or d, according to the voltage desired.

For explanation purposes only the grid is shown connected to, the point c of the vcoil system L. The arrangement of parts and the adjustments of the same are such that the system will oscillate at the A frequency with the coil L set at a position parallel with the coil L and will regenerate between this oscillating position, hereinafter designated as the position, and the position at approximately 90 degrees with the coil L, that is at the position of zero coupling. When the coil 1 is between the 0 and 90 degree position the system will be found to be resonant at the A frequency whether the switch 3 is closed or open.

' With all other conditions and constants remaining the same, I have found that the system will regenerate and oscillate at a frequency other than the A frequency if the switch 3 is closed and the coil L is in a position between 90 and 180 degrees from the 0 position. This frequency will hereinafter be referred to as the Bfrequency.

The system as shown in Figure 1 is resonant at two definite frequencies according to the position of the coil L and the'condition of the switch 3.

-. I have found further that the points and e may or'may not be connected together without changing the B."frequency. This I have accomplished by means of the connection H in which there is a switch 10;

However, if the points a and e are connected together by the wires 4 and 5 and the switch lo. the system is non-resonant to the "A" frequency. Thus, referring to Figure 1, if the switches 3 and are open the system is resonant to the "A" frequency. If the switches 3 and-10 are closed the system is resonant to the B frequency. By means of this arrangement it is possible to reduce to a minimum the tendency of the coil system L to respond to energy other than that transmitted through the medium of the coil L at the B frequency. By closing the switch 10 I remove the tendency of the coil and vacuum tube combination-to respond to, regenerate, or oscillate at the A" frequency,-the tendency of the. coil system L functioning as a 1001: being to respond to signals of the B frequency and to be practically non-resonant to frequencies slightly removed from that frequency.

When the points a and e are connected together, they are at the same potential withrespect to each other but both points are at an equal and opposite potential with respect to the points cc. The current flow in the section ac of the coil system is equal and opposite to the current flow in the section ce as indicated by the dotted arrows in Figure 2. All extraneous disturbances that would tend to induce a current in the section ac are neutralized for the reason that the current flows in the same direction as the current induced in the section ce and in the opposite direction to the current flowing in the coil system ce functioning at the B frequency.

' In the position shown in Figure 1, the coil I will impart energy equally to sections ac and ce of coil system L With the points a and e connected together and with points 0 and c not connected together, the coil system ac will not respond to currents of either the A or the B frequency transmitted by the coil L If the switch 10 is opened, the system by reason of the tight coupling between the coils L and L will respond readily to currents of the B frequency while the same non-responsive condition will prevail with respect to currents of the A frequency in the coil L With the switch 10 open or closed and with switch 3 closed, the desired amount of energy of the A frequency in the coil L may be transmitted to the coil system H by changing the position of the coil L with respect to the electrical center of the coil system ae as shown by the arrow 11. The circuit disclosed in Figure la operates in a similar manner but the transfer of current from the coil I to the coil system (1-2 is at the B frequency.

In the circuit shown in Figure 2, I have inserted. an inductance L in the connection. c -c', and have substituted a capacity C in the place of the switch 10 of Figure l. The inductance L does not affect the A. frequency and the capacity ('3 does not affect the "8 frequency for the reason that these two additional units are connected across the nodal points of the respective circuits.

However, the value of the A frequency is affected by the capacity factor 0 Also the value of the .B frequency is affected by the inductance factor L Although shown as inductance and capacity it will be understood that the units may be inductance-s or capacities or combinations of both.

Since in the coil system L the points a and e, are connected together in such a manner that the 3" frequency and not the A frequency will prevail, the system responds as desired to the energy-received from coil L". If coil L is in the plate circuit of a vacuum tube amplifier, it should carry "3 frequency only. This requires that the grid of the vacuum tube amplifier should receive energy at B" frequency only. Figure 2 shows one type of arrangement by which this result may be accomplished. The antennaground circuit is shown tightly coupled'to coil system ac with respect to the A frequency,

and in effect loosely or variably coupled as desired to the coil system a-e with respect to the "3 frequency. Since coil L is in the 13" frequency circuit, it functions independently of the current flow in coil system ac at the A frequency. Coupled to coil L is a tuned B frequency circuit consisting of an inductance L with'a tuning condenser C in parallel therewith which constitutes the inputof a detector or amplifying circuit as desired. 1

It is known that most undesirable interferences arise from damped oscillatory discharges and shock excitations, such'as static, strays andother causes. Due to the tightcoupling between coil L and. coil system L at the. A frequency, the shock or damped energy will cause coil system L to oscillate at the A frequency but this excitation does not affect the coil L By reason of the effective loose coupling atthe' B frequency between coil L and coil system L the latter will respond at the B frequency to the B frequency energy received by the antenna system. This response will be transmitted through the medium of coil L to the detector or amplifier circuit coupled to coil L Spurious excitations of the antenna system that cause it to oscillate at the A" frequency, the period predetermined by the effect of the tight coupling to the coil system L at this A frequency, will not be transmitted to the coil L and the detector or amplifier circuit coupled thereto. In this manner the detection or amplification of undesired interferences of whatever kind or type is reduced to a minimum.

Variation of the values of the A and the B frequencies is accomplished by varying the separation of the two halves (a c and 0-6) of inductance coil system a-e and also by ad-. justing the values of the units, if any, betwee points e and c and points a and e.

Referring to Figure 1a, the current flow at the B frequency being equal and in opposite. directions in the two halves of the coil system a 'e, if such a coil system is to be used as an oscillator at the B frequency, the opposing fields tend to neutralize undesirable effects of coupling to separate, distinct and distant circuits. In this manner interference caused by the function of the coil system ae as a generator and transmitting or radiating energy is eliminated. In the Figures 1 and 2 the elimination of extraneous disturbances is accomplished, if the coil system be an oscillator at the A frequency.

Further modifications are shown in Figures 3 and 4 the detail operation and construction of which are considered obvious from the foregoing description of the simple circuit.

Referring to Figure 3, 1 represents a vacuum tube oscillating at the A frequency and 2 represents a vacuum tube so arranged that it detects at the 3" frequency. The grid 6 of vacuum tube 2 is connected to coil L through variable connection 12 which controls the potential upon the grid 6'.

Figure 4 represents a circuit in which vacuum tube 1 is oscillating at the B frequency and vacuum tube 2 is detecting at the A frequency.

Either of the circuits shown in Figures 3 and 4 are adaptable to either simultaneous reception and transmission of signals or may be used in heterodyne reception, the frequency of the resultant long wave being the difference in frequency between the A and B frequency.

As an alternative the filament may be connected to corresponding potential points of the coil system ae instead of to the condenser system as shown, without affecting the functioning of the system. Also one tube may function as an oscillator on one frequency while the other tube operates as a detector upon the other frequency.

In any of the circuits disclosed all of the tubes are capable of functioning at two frequencies in the following manner.

In Figures 1, 1a and 2 the one tube may act as a detector at one frequency and simultaneously as an oscillator at the other frequency, detect at both frequencies or oscillate at both frequencies.

Inithe circuits shownin Figures 3 and 4 one tube may be substituted for the two tubes to obtain the results heretofore described by merely using the well knownmethods of blocking or by-passing,the alternating and direct currents in the circuit as required.

It. willbe understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of my invention and that minor detail changes in the construction and arrangement of parts may be made within the scope of the appended claims without sacrificing any of the advantages of my invention. 1

Having thus described my invention what I claim is as follows:

1.Incombination, a coil system comprising a plurality of sections, condensers in parallel with each section. and means for regeneration at the resonant frequency of the entire system and for regeneration at the resonant frequency of the-individual sections independent of the resonant frequency of the entire system, the said means comprising a coil coupled to the entire system and rotatable through 180 degrees of coupling with the coil system.

2. In eombination,'a coil system comprising aplurality of sections, a condenser in parallel with each section, said sections being inductively coupled together'to produce a circuit resonant at a plurality of frequencies, a vacuum tube, the electrodes of which are-connected to the coil system at a plurality of points, and an input coil inductively coupled to the system and variably coupled with reference to the sections to activate the vacuum tube at a single resonant frequency of the coil system.

3. In combination, a coil system comprising a plurality of sections, a condenser in parallel with each section, said sections being inductively coupled together to produce a circuit resonant at a plurality of frequencies, a vacuum tube, the electrodes of which are connected to the coil system at a plurality of points, and an input coil inductively coupled to the system and variably coupled with reference to the sections to activate the vacuum tube at the frequency determined by the additive inductance of the sections.

4. In combination, a coil system comprising a plurality of sections, a condenser in parallel with each section, said sections being inductively coupled together to produce a circuit resonant at a plurality of frequencies, a vacuum tube, the electrodes of which are connected to the coil system at a plurality of points, and an input coil inductively coupled to the system and variably coupled with reference to the sections to activate the vacuum tube at the frequency determined by the subtractive inductance of the sections.

5. In combination, a coil system comprising a plurality of sections, a condenser in parallel with each section, said sections being inductively cou pled together to produce a circuit resonant at a plurality of frequencies, means responsive to high frequency connected to said system at a plurality of points, and an input coil inductively coupled to the system and variably coupled with reference to said sections to activate said means at a single resonant frequency of the system.

6. In combination, a coil system comprising a at a plurality of points, and an input coil. inductively coupled to the system and variably coupled with reference to the sections to activatesaid means at a plurality of frequencies.

'7. In combination, a coil system comprising a plurality of sections, a condenser in parallel with each section, said sections being inductively coupled together to produce a circuit resonant at a plurality of frequencies, means responsive to high frequency currents connected to said system at a plurality of points, and an input coil inductively coupled to the system and variably coupled with reference to the sections to activate said. means at the frequencies determined by the additive and the subtractiveinductance of the sections of the system.

. 8. 'In a signaling system a network responsive to more than one frequency comprising two resonant sections, associated in parallel through a common inductance element to determine one responsive frequency and associated in series exclusive of said common inductance element to determine another responsive frequency a second inductance element coupled to the first said inductance element responsive to one only of said frequencies and a third inductance element bilaterally coupled to the inductances of both of said resonant sections to excite said network at at least one of said frequencies.

9. In combination, a coil system comprising a plurality of sections, condensers in parallel with at least two of said sections and means for regeneration, at the resonant frequency of the entire system and for regeneration at the resonant frequency of the individual sections independent of the resonant frequency of the:entire system, the said means comprising a coil variably coupled to the said coil system.

10. In a signaling system a high frequency filter network responsive to more than one frequency comprising" two resonant sections associated in parallel through a common metallic circuit to determine one responsive frequency and associated in series exclusive of said common metallic circuit to determine another responsive frequency an input coil bilaterally coupledwith the inductances of saidvres'onant sections, and means for varying the coupling between the input coil and the inductances of said resonant sections and for varying the coupling between said resonant sections for varying at least one of said resonant frequencies.

11. In combination a filter network responsive to more than one frequency comprising two resonant sections associated in parallel through a common metallic circuit to determine one responsive frequency and associated in series independent of said common metallic circuit to determine another responsive frequency and an input coil inductively coupled to the inductances of each of said two resonant circuits to bilaterally excite saidvnetworkat at least one of said frequencies.

' JAMES E. PARKER. 

